Since recent years, electronic appliances are required to consume lower power to reduce the load on the environment. A way of achieving lower power consumption is to reduce the power consumption of integrated circuits (e.g., LSI devices: large scale integration devices) mounted on electronic appliances.
An integrated circuit includes a flip-flop which is a kind of logic circuit. Examples of flip-flops include not only a simple flip-flop which obtains data in accordance with the pulse of a clock signal, but also a flip-flop having a reset terminal, a flip-flop having a set terminal, and a flip-flop having a reset terminal and a set terminal. These flip-flops each have a latch circuit having a function of holding data (see for example Patent Document 1). Further, a flip-flop having a reset terminal, a flip-flop having a set terminal, and a flip-flop having a reset terminal and a set terminal each additionally have a NAND circuit, and the like.